1. Field of the Invention
The present invention relates to a production method of a suspension board with circuit.
2. Description of the Related Art
Conventionally, a suspension board with circuit has been known which includes a metal supporting layer, an insulating layer formed on the metal supporting layer, a conductive layer formed on the insulating layer, having signal wires and terminal portions connected thereto, and a metal thin film interposed between the conductive layer and the insulating layer.
In the production of such a suspension board with circuit, e.g., after second openings are formed in an insulating layer, and a conductive layer is formed to fill the second openings, pad portions are formed on terminal portions using a metal supporting layer as a lead portion for electrolytic plating. Thereafter, to prevent a short circuit between the metal supporting layer and the conductive layer, it has been proposed to bore first openings in the portions of the metal supporting layer opposing the second openings such that the first openings surround the individual second openings, and are kept from contact with the peripheral edges of the second openings (see, e.g., Japanese Unexamined Patent Publication No. 2005-100488 (FIGS. 2 and 3)).